US-20260125045-A1 - HYBRID VEHICLE

Abstract

A hybrid vehicle includes an engine, a fan that rotates in conjunction with the engine, a first motor connected to the engine and provided on a power transmission path between the engine and a driving wheel, a second motor provided on the power transmission path, a torque converter provided on the power transmission path between the first motor and the second motor, a first power control unit configured to control electric power to the first motor, a second power control unit configured to control electric power to the second motor, a motor radiator that is cooled by the fan and promotes heat dissipation of cooling water circulating through the first and second motors and the first and second power control units, and a vehicle control unit.

Inventors

• Makoto Yoshioka

Assignees

• TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date

20260507

Application Date

20250908

Priority Date

20241107

Claims (4)

1. 1 . A hybrid vehicle comprising: an engine; a fan that rotates in conjunction with the engine; a first motor connected to the engine and provided on a power transmission path between the engine and a driving wheel; a second motor provided on the power transmission path; a torque converter provided on the power transmission path between the first motor and the second motor; a first power control unit configured to control electric power to the first motor; a second power control unit configured to control electric power to the second motor; a motor radiator that is cooled by the fan and promotes heat dissipation of cooling water circulating through the first and second motors and the first and second power control units; and a vehicle control unit configured to control the second power control unit to cause the hybrid vehicle to travel by the second motor and to control the first power control unit to cause the first motor to rotate the fan via the engine in a motor traveling mode in which combustion in the engine is stopped.
2. 2 . The hybrid vehicle according to claim 1 , wherein the vehicle control unit is configured to control the second power control unit to cause the hybrid vehicle to travel by the second motor, when a travel request is made in the motor traveling mode and a required driving force of the hybrid vehicle is equal to or less than a threshold value, and the vehicle control unit is configured to control the first and second power control units to cause the hybrid vehicle to travel by the first and second motors, when the travel request is made in the motor traveling mode and the required driving force is larger than the threshold value.
3. 3 . The hybrid vehicle according to claim 2 , further comprising: an automatic transmission provided on the power transmission path between the torque converter and the second motor; and a first clutch provided in the automatic transmission, wherein the vehicle control unit is configured to cause the first clutch to engage when the hybrid vehicle travels in the motor traveling mode, and the vehicle control unit is configured to cause the first clutch to disengage, to control the second power control unit to stop the second motor, and to control the first power control unit to rotate the fan by the first motor via the engine, when the hybrid vehicle is stopped in the motor traveling mode.
4. 4 . The hybrid vehicle according to claim 3 , further comprising a second clutch provided on the power transmission path between the engine and the first motor, wherein the vehicle control unit is configured to cause the second clutch to engage in the motor traveling mode.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2024-195423, filed on November 7, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a hybrid vehicle. BACKGROUND A hybrid vehicle is known. The hybrid vehicle is equipped with an engine, a fan that rotates in conjunction with the engine, a motor, a power control unit that controls electric power to the motor, and an engine radiator that is cooled by the fan (for example, see Japanese Unexamined Patent Application Publication No. 2016-112933). In order to ensure the cooling performance of the motor and the power control unit, a motor radiator may be provided in addition to the engine radiator. In this case, in the motor traveling mode in which the engine is stopped and the vehicle travels by the motor, the fan is also stopped. Therefore, the motor radiator might not be sufficiently cooled, and the motor and the power control unit might not be sufficiently cooled. In the motor traveling mode, a decrease in the power of the motor might cause a decrease in the traveling performance. SUMMARY It is therefore an object of the present disclosure to provide a hybrid vehicle that ensures cooling performance of motors and power control units while ensuring traveling performance in a motor traveling mode. The above object is achieved by a hybrid vehicle including: an engine; a fan that rotates in conjunction with the engine; a first motor connected to the engine and provided on a power transmission path between the engine and a driving wheel; a second motor provided on the power transmission path; a torque converter provided on the power transmission path between the first motor and the second motor; a first power control unit configured to control electric power to the first motor; a second power control unit configured to control electric power to the second motor; a motor radiator that is cooled by the fan and promotes heat dissipation of cooling water circulating through the first and second motors and the first and second power control units; and a vehicle control unit configured to control the second power control unit to cause the hybrid vehicle to travel by the second motor and to control the first power control unit to cause the first motor to rotate the fan via the engine in a motor traveling mode in which combustion in the engine is stopped. The vehicle control unit may be configured to control the second power control unit to cause the hybrid vehicle to travel by the second motor, when a travel request is made in the motor traveling mode and a required driving force of the hybrid vehicle is equal to or less than a threshold value, and the vehicle control unit may be configured to control the first and second power control units to cause the hybrid vehicle to travel by the first and second motors, when the travel request is made in the motor traveling mode and the required driving force is larger than the threshold value. The hybrid vehicle may further include: an automatic transmission provided on the power transmission path between the torque converter and the second motor; and a first clutch provided in the automatic transmission, wherein the vehicle control unit may be configured to cause the first clutch to engage when the hybrid vehicle travels in the motor traveling mode, and the vehicle control unit may be configured to cause the first clutch to disengage, to control the second power control unit to stop the second motor, and to control the first power control unit to rotate the fan by the first motor via the engine, when the hybrid vehicle is stopped in the motor traveling mode. The hybrid vehicle may further include a second clutch provided on the power transmission path between the engine and the first motor, wherein the vehicle control unit may be configured to cause the second clutch to engage in the motor traveling mode. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration view of a hybrid vehicle; FIG. 2 is a schematic configuration view of a cooling system; and FIG. 3 is a flowchart illustrating motor traveling control. DETAILED DESCRIPTION Schematic Configuration of Hybrid Vehicle FIG. 1 is a schematic configuration view of a hybrid vehicle 1. The hybrid vehicle 1 is equipped with an engine 10, a first motor 15, and a second motor 22 as power sources for traveling. The engine 10 is a gasoline engine having a plurality of cylinders, but may be a diesel engine or a hydrogen engine. The engine 10 is disposed on the front side of the hybrid vehicle 1. The hybrid vehicle 1 includes rear wheels 31 and front wheels 32. On a power transmission path from the engine 10 to the rear wheels 31, a K0 clutch 14, the first motor 15, a torque convertor 16, an automatic transmission 17, a sub-transmission 18, a transfer 20, a rear propeller shaft 21, the second motor 22, a